CONCENTRIC AND ECCENTRIC KINEMATIC RECOVERY OF STROKE SURVIVORS AFTER A SINGLE TRAINING SESSION

Introduction: Stroke impairs arm kinematic motor control. Recovery of kinematic properties (e.g., smoothness) is crucial for achieving true recovery and occurs mostly during the first 5 weeks after the stroke. It is unknown whether this recovery is possible in later stages.
Methods: 37 stroke survivors performed a 70-trial single-training session with the paretic shoulder flexo-extension movement following sinusoid patterns on a computer using a motion sensor. We evaluated the training effect in smoothness of movement via SPARC, comparing the change between the initial (block 1; B1) and final (block 7; B7) data within each group and differences between groups in the magnitude of change (B7-B1), at three stroke stages: Early subacute within the first month (ESA1, n=12), Early subacute within the third month (ESA3, n=12), and Chronic stage (CHR, n=13). Concentric and eccentric phases of the task were analyzed separately due to differences in movement control.
Results: The mean age of the sample was 63 (13.64) years. 43% were female. The sample characteristics were similar across groups. There were no changes in SPARC in the concentric phase during the training; ESA1:W=42,p>0.05; ESA3:W=49,p>0.05; CHR:W=39,p>0.05 (Fig.1A). For the eccentric, all groups improve their smoothness; ESA1:t=-2,38,p<0.05; ESA3: t=-2.53,p<0.05; CHR:t=-3.12,p<0.01 (Fig.1B). Considering the magnitude of change, all groups have similarly variations (concentric: F=0.146,p>0.05; eccentric: F=0.251,p>0.05).
Discussion: The recovery of kinematic control in the trained task is different depending on the control phase. Improvements in the eccentric phase were possible at all post-stroke stages. This could lead to a new training framework to improve kinematics.